The present invention relates to a telephone answering system including a telephone line concentrator for concentrating calls from a plurality of subscriber lines to an answering station.
For many years now it has been common practice for answering services to service a large plurality of subscriber lines at times selected by the subscriber. Such telephone answering services answer calls to the subscriber lines either at preselected times selected by the subscriber or if the incoming call to the subscriber line rings more than a predetermined number of times. Under such situations, the call is then taken by the operator at the remote answering station due to the current unavailability of the subscriber.
For this purpose, a plurality of subscriber lines within the same central office are coupled to a concentrator for concentrating all of the incoming calls from the subscriber lines. The answering station is then coupled to the concentrator by a plurality of dedicated lines. Each line includes two wires extending from the concentrator to the answering station. Such dedicated lines are direct connections especially made between the concentrator and the answering station. Typically a plurality of such lines are connected between the locations for serving as talk paths. In addition, at least one data communication line is connected between the concentrator and the answering station. Identification information is transmitted over the data communications line. Such identification information identifies the particular subscriber line to which an incoming call was directed so that the operator knows which subscriber line the operator is answering.
Typically, the identification information for all calls that have been received by the concentrator is immediately transmitted to the answering station where such information is maintained. It is common to display all of the identification information for the calls awaiting answering on a video screen with the operator then being able to select the calls one at a time for answering. While it is common to use a video screen presenting all of the identification information concerning all of the calls awaiting answering, such identification information has also been conveyed to a loudspeaker in the room so that the information can be heard by the operator. This latter type of system has been used where the operators answering the phones were blind.
Exemplary of the types of telephone answering systems including concentrators that have typically been utilized within the prior art are those systems disclosed by U.S. Pat. Nos. 2,971,061, 3,002,054 and 3,987,252. Each of these patents discloses a system in which the concentrator of the answering system is coupled to a plurality of subscriber lines and a plurality of output lines are coupled from the concentrator to the answering station. As indicated in U.S. Pat. No. 2,971,061 to Judy, data between the concentrator and the answering service is transmitted over a separate line so as to notify the answering service that a call is being received by the subscriber. In U.S. Pat. No. 3,002, 054 to Krom, a telephone answering system is disclosed in which a minimum of four trunk pairs of lines are connected between the central office which serves as a concentrator and the answering service center. Of the four trunk lines, three of the lines are used for the interchange of timing and control signals while the fourth line serves as a talking path to connect the answering center operator with any subscriber line to which a call is currently directed. In U.S. Pat. No. 3,987,252, a telephone answering system is disclosed that has eight lines interconnecting each of the concentrators to the central answering location.
Another patent in which a telephone answering system is disclosed which includes an arrangement for operating a call announcer to announce a fixed arbitrary character is U.S. Pat. No. 2,314,990 to Kessler. In the answering system disclosed by such patent, a plurality of trunk lines including indicator trunk lines are connected between the central office and the answering service. The system includes a call register-announcer device that is adapted to first register and then to announce or display the called telephone number to the selected operator position and to identify the calling cord circuit of the switchboard in the associated group. The operator at the selected operator position can then set up the call as announced by way of the plug terminating the calling cord circuit and the jack terminating the called line. The connection is then established and the call is answered.
An answering service system that utilized only a single line between the telephone company switching center and the telephone answering bureau that has been tried in the past is a shared line system. Such a system is illustrated in FIG. 4 of the drawings. A shared line system is a telephone rented from the telephone company by the telephone answering service for transfer of subscribers lines. A subscriber wishing to have his telephone answered on this system must have a transfer switch on or near his residence or office telephone. When the switch is thrown, the telephone no longer rings at the premise of the subscriber. Instead, the subscriber telephone rings the telephone that is rented to the answering service through a transfer relay located in the telephone company. While many subscribers can be handled over such a shared line system, the answering service may only handle one call at a time. If one call is connected to the answering service then any subsequent callers to any of the other subscribers receive a busy signal. In essence, such an arrangement forms a special shared party line.
Another type of answering service system is one where the calls to the subscriber lines are diverted to a telephone answering system, often referred to as TAS, such as shown in U.S. Pat. No. 3,704,346. In the system disclosed an identification code can be sent to the second line answering the call.